Method of making relatively thin vinyl films



Aug. 28, 1962 R. A. JEROTHE METHOD OF MAKING RELATIVELY THIN VINYL FILMS United States Patent Oli-ice York Filed Dec. 16, 1959, Ser. No. 859,937 2 Claims. (Cl. 18-57) This invention relates to an improved method for making relatively thin vinyl lms, and particularly for making vinyl films of less than about 1.5 mils thickness.

Various techniques and apparatus have been utilized heretofore for the manufacture of vinyl films. Usually these require relatively heavy and expensive calender or casting equipment so that the manufacture of vinyl lms has been conned to relatively large companies with heavy capital equipment investments. However, even with equipment of this type the casting of relatively thin or the rolling of relatively thin vinyl lms, for example of less than about 2 mils in thickness has resulted in films of non-uniform thickness from edge to edge of the film, and defects such as pin holes and surface imperfections.

Y It is the general object of the present invention to provide an improved process for rapidly and inexpensively manufacturing unsupported relatively thin vinyl films, for example of less than about 1.5 mils thickness, and down to .5 mil, of uniformly high grade quality and the same gauge from side to side of the ilm, the process being relatively quickly and easily performed with comparatively light and inexpensive apparatus capable of being installed in the plant of a user or a fabricator of vinyl films.

Another object of the invention is the provision of a method in which thin gauge vinyl lms of high polish or other surface finish and excellent uniformity can be btained with a minimum of operator control and attention.

The foregoing objects of the invention, and other objects which will become apparent as the description proceeds, are achieved by the provision of a method of making relatively thin vinyl films of less than about 1.5 mils thickness which include the steps of continuously passing a temperature resistant plastic film having a desired surface finish over an elongated path, continuously applying a vinyl plastisol to the surface of the plastic lrn to forma uniform surface coating of less than about 1.5 mils thickness over the plastic ilm, continuously heating the vinyl plastisol while applying pressure thereto to fuse the plastisol into a vinyl lm, contin-v uously cooling the laminated films, continuously separating the vinyl film from the plastic film, and continuously but separately winding up the vinyl film and the plastic film. The method preferably includes the continuous polishing of the vinyl tilm against the plastic film while still hot, and the separation of the vinyl film from the plastic film after cooling. Also, the vinyl plastisol is preferably applied to the surface of the plastic lihn as a series of dots normally in excess of 2,000 to the square inch and positioned sutiiciently close together and with the plastisol suliciently liquidthat the dots run together before or during the application of heat and pressure to form the uniform surface coating of vinyl'plastisol Over the plastic film.

For a better understanding of the invention reference should be had to the accompanying drawings wherein FIG. l is a diagrammatic side elevation of a typical apparatus utilized to perform the method of the invention;

FIG. 2 illustrates a preferred method of making a vinyl film having one side polished and the other side matte or embossed; and

FIG. 3 is a fragmentary View of a portion of the apparatus of FIG. l and illustrating another manner of cool- Patented Aug. 28, 1962 ing and separating the vinyl film from the temperature resistant plastic film. v

In the drawings, the numeral 10 indicates a roll of temperature resistant plastic lrn or a carrierweb 12. This lm may be of the polyester type sold by E. I. du Pont de Nemours & Company of Wilmington, Delaware under the trademark Mylan The film-12 is not softened by the temperatures to which it is subjected in the method of the invention, but is stress relieved so as to lie laterally iiat against the heat drum utilized in the method. ln addition, the lilm 12 possesses a relatively high polish, is comparatively thin, being only several mils thielcbut is tough and strong.

The film 12 is passed over a rubber 'roll 14 and in the continuous elongated path illustrated in FIG. 1. Cooperating with the roll la is a gravure roll 16 having in association therewith a blade 1S for supporting a pocket of vinyl plastisol 2t? against the surface of the roll 16.' Preferably only roll 14 is driven and roll 16 is adjustably mounted for movement toward and from roll 14 by means of nuts on screw 17.

The gravure roll 16 is more fully described in my copending patent application Serial No. 856,241, filed Nov. 30, 1959, now Patent Number 3,036,927, and entitled Method of Coating Vinyl Film With a Surfacing Color. Suffice it to say here that the roll 16 is engraved over its entire surface with a relatively large number of pockets or cups, usually in excess of 2,000 per square inch, each cup being filled with vinyl plastisol as the roll turns in the direction of the arrow underneath the vinyl plastisol held by the blade 18, with the vinyl plastisol in the cups being transferred from the surface of the cups to the surface of the plastic film 12 by the adjustable pressure engagement of roll 16 against the film 12. This produces on the surface of the temperature resistant plastic film 12 a plurality of dots of vinyl plastisol, usually in excess of 2,690 per square inch, the dots being very close together, and with the vinyl plastisol of a consistency so that the dots coalesce or unite on the surface of the plastic film 12 to form a continuous highly uniform relatively thin layer of vinyl plastisol of less than about 1.5 mils thickness and as thin as .5 mil if desired on the surface of the plastic film 12 as the hlm passes in the direction of the arrow from the rubber r'oll A12. This coalescing of the dots of plastisol normally occurs during or immediately after deposit and is completed under the heat and pressure applied to the plastisol on the drum 24.

The plastic lm 12 with the layer of vinyl plastisol 2l) thereon is pressed by a roll 22 into pressure engagement with a heat drum 24 held, for example, at a temperature of 325 F., and with the drum turning in the direction of the arrow` The tension in the plastic lm 12 holds the vinyl plastisol under pressure against the heat drum 24, and with the speed of rotation of the drum and the length of its heating surface being such that together with the selected temperature of the drum the vinyl plastisol 20 on the surface of the plastic film 12 is completely set up or fused by the time the laminate leaves the surface of the heat drum as it bends around a roller 26.

The laminate indicated by the numeral 'l2-20 passing over the roll 26 passes to and between driven polishing and tensioning rollers 28 and 3i), roller 28 normally being of rubber and with the rolls rotating in the direction of the arrows so that a polishing action is obtained upon the still hot vinyl lm 2i). The pressure between rolls 28 and 30 is preferably made adjustable as by nuts on screw 2 lt should be noted here that the invention broadly teaches providing a matte iinish on the carrier film 12 instead of a high polish so that the finished vinyl lilm 20 has a matte surface. However, it is preferable to provide a polished surface against the carrier film 12..

ensayar polishing rolls 28o and 30a.

` Vchanged and the metal roll 30a is formed with the desired Vmatte or embossed design to be pressed into the hot formable surface of the vinyl lm as it leaves the heat drum 24.

Leaving the polishing rolls V28 and 30 the vinyl ilm 20 passes under roll 31, around cooling rolls 33 and Vafter cooling is stripped from the plastic nlm 12, with the Vvinyl film 20 being rolled up at r32 and the plastic hlm 12 being wound up at 34.

In the manner described'it is possible to rapidly and uniformly make high quality relatively thin vinyl til-m, bearing a high polish, and of very excellent and uniform gauge. The method of the invention is adapted for use with relatively light and inexpensive equipment 4which can be made available in the plant of a user or fabricator of vinyl lms as Vdistinct from the heavy equipment normally required by the vinyl iilm manufacturer.

ln the practice of the method of the invention it will Vbe understood that the mannerof applying the vinyl plastisol to the heat resistant plastic film is very important, and the gravure roll technique utilized has been proven r to be satisfactory whereas attempts to apply the plastisol by lmeans of a doctor bar or the like are completely unsatisfactory resulting in streaking and non-uniform gauge to such an extent that commercially salable unsupported lm cannot be produce-d. n Y

FIG. 3 illustrates another method for stripping the laminate lITP-Zt) after it passes through pressure and More particularly, in this embodiment of the invention the laminate 1220 as it passes from rolls ZSa-Stia extends over a cooling drum 50, withl the temperature resistant iilm 12 being stripped from the vinyl film 2d while it is stl held on the cooling drum by means of a roll 52 and a plastic film windup 54.

,The vinyl film 2li is passed over a roll 56 and -to a windup 58 after it has passed over an additional periphery of the cooling drum 50.

While in accord, known embodiments of the invention have been illustrated and described in detail, it is to be particularly understood that the invention is not to be limited thereto or thereby, but that its scope is deined in the appended claims,

What is 'claimed is:

1. That method of making unsupported relatively thin vinyl yiilms of less than about 1.5 mils thickness which includes the steps of continuously passing a temperature resistant plastic iilm having a highly polished, smooth,

K Vand non-porous surface through an elongated path, con

tinuously applying a plurality of dots of vinyl plastisol to the surface of the plastic film, said vinyl plastisol dots being normally in excess of two thousand to the with the patent statutes certain best square inch and positioned suiciently close together and with the plastisol suiciently liquid so that the dots run together and form a uniform surface coating of less than about 1.5 mils thickness over substantially the entire plastic iilm, applying pressure uniformly toV the vinyl plastisol as it is led through a confined path of movement, continuously heating the vinyl plastisol While under pressure to Vcomplete the continuously cooling the laminated iilrns, continuously separating the vinyl tilm when cooled from theplastic lilm, and continuously -winding up the vinyl iilm.

2. That method of making unsupported relatively thin vinyl lms of less than about v1.5 mils thickness which includes the Steps of continuously passing a temperature v resistant non-porous plastic film having a Ahighly polished surface over an elongated path, continuously applying by printing with adjnstably controllable pressure a plurality of Vspaced dots of vinyl plastisol to the surface of the plastic lm, said vinyl plastisol dots being normally in excess of two thousand to the square inch, continuously carrying the printed lm substantially horizontally and with the dots uppermost and with the plastisol sutliciently liquid so that the dots run together and form a uniform surface coating of less than about 1.5 mils thickness over lsubstantially the entire plastic iilm, continuously heating the plastic film, and continuously but separately winding up the vinyl iilm and the plastic hlm.

References Cited in the le of this patent UNITED STATES vPATENTS OTHER REFERENCES Its Done With Plastisols, from Modern Plastics, December, pp. 87-93, 184, 186, 189, 191 and 193.

coalescing of the dots into a uniform iilm and to fuse the plastisol into a Vinyl film, 

1. THAT METHOD OF MAKING UNSUPPORTED RELATIVELY THIN VINYL FILMS OF LESS THAN ABOUT 1.5 MILS THICKNESS WHICH INCLUDES THE STEPS OF CONTINUOUSLY PASSING A TEMPERATURE RESISTANT PLASTIC FILM HAVING A HIGHLY POLISHED, SMOOTH, AND NON-POROUS SURFACE THROUGH AN ELONGATED PATH, CONTINUOUSLY APPLYING A PLURALITY OF DOTS OF VINYL PLASTISOL TO THE SURFACE OF THE PLASTIC FILM, SAID VINYL PLASTISOL DOTS BEING NORMALLY IN EXCESS OF TWO THOUSAND TO THE SQUARE INCH AND POSITIONED SUFFICIENTLY CLOSE TOGEHTER AND WITH THE PLASTISOL SUFFICIENTLY LIQUID SO THAT THE DOTS RUN TOGETHER AND FORM A UNIFORM SURFACE COATING OF LESS THAN ABOUT 1.5 MILS THICKNESS OVER SUBSTANTIALLY THE INTIRE PLASTIC FILM, APPLYING PRESSURE UNIFORMLY TO THE VINYL PLASTISOL AS IT IS LED THROUGH A CONFINED PATH OF MOVEMENT, CONTINUOUSLY HEATING THE VINYL PLASTISOL WHILE UNDER PRESSURE TO COMPLETE THE COALESING OF TH DOTS INTO A UNIFORM FILM AND TO FUSE THE PLASTISOL INTO A VINYL FILM, CONTINUOUSLY COOLING THE LAMINATED FILMS, CONTINUOUSLY SEPARATING THE VINYL FILM WHEN COOLED FROM THE PLASTIC FILM, AND CONTINUOUSLY WINDING UP THE VINYL FILM. 